Amsterdam, The Netherlands, May 26, 2009 – There are several risk factors for the development of Alzheimer's disease and vascular dementia. Based on an increasing number of studies linking these risk factors with Vitamin D deficiency, an article in the current issue of the Journal of Alzheimer's Disease (May 2009) by William B. Grant, PhD of the Sunlight, Nutrition, and Health Research Center (SUNARC) suggests that further investigation of possible direct or indirect linkages between Vitamin D and these dementias is needed.
Low serum levels of 25-hydroxyvitamin D [25(OH)D] have been associated with increased risk for cardiovascular diseases, diabetes mellitus, depression, dental caries, osteoporosis, and periodontal disease, all of which are either considered risk factors for dementia or have preceded incidence of dementia. In 2008, a number of studies reported that those with higher serum 25(OH)D levels had greatly reduced risk of incidence or death from cardiovascular diseases.
Several studies have correlated tooth loss with development of cognitive impairment and Alzheimer's disease or vascular dementia. There are two primary ways that people lose teeth: dental caries and periodontal disease. Both conditions are linked to low vitamin D levels, with induction of human cathelicidin by 1,25-dihydroxyvitamin D being the mechanism.
There is also laboratory evidence for the role of vitamin D in neuroprotection and reducing inflammation, and ample biological evidence to suggest an important role for vitamin D in brain development and function.
This could be done with either blood tests of vitamin D levels or vitamin D supplementation.
Given these supportive lines of evidence, Dr. Grant suggests that studies of incidence of dementia with respect to prediagnostic serum 25(OH)D or vitamin D supplementation are warranted.
The advantage of vitamin D supplementation over blood tests is that high blood vitamin D might be a marker for other things that reduce risk of Alzheimer's. For example, a person with a more slowly aging brain might get outside more often, get more sunlight on their skin, and therefore have more vitamin D in their blood. Or diseases could lower blood vitamin D and also increase risk of Alzheimer's at the same time.
The problem with prospective studies is that they cost a lot and take a long time. You really do not want to find out 10 or 15 or 20 years from now that vitamin D is protective since damage that leads up to an Alzheimer's diagnosis probably begins many years earlier. People in middle age and later need to cut their disease risks starting now. Since I do not want to wait for the evidence to become definitive I'm already taking vitamin D.
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